1. Field of the Invention
The present invention relates to stub axles and stub shafts that are utilized primarily in combination with cartridge bearings. Generally, the cartridge bearing combination is sized for coacting with an end of conventional roller tubes mounted to conveyor frames. Although the stub axle is retractable, the spring positioned inside the stub shaft normally urges the stub axle toward its corresponding aperture located in the conveyor""s frame. Along with being anchored to the stub shaft, the stub axle is also provided with a tip that is harder than the exposed surface circumscribing its corresponding aperture of the frame""s fixed structure. The harder tip positioned near the end of the stub axle functionally or operatively interlocks the aperture to reduce scoring of the stub axle caused by operational vibrations of the conveyor. Along with increasing the longevity of the stub axle, the harder tip provides for easier removal of the stub axle from the frame, since the scoring of the stub axle has been reduced. In select embodiments, a nonmetallic damper is located between the stub axle""s body and tip for reducing vibration between the stub axle and the conveyor frame.
2. Description of the Previous Art
a) U.S. Pat. No. 6,053,298-Nimmo, et. al., discloses a conveyor roller assembly. Roller tube (16) is rotably supported by bearing unit (20) that includes a ball bearing (22) having an outer race confined within an annular adapter bushing (24) molded of a rigid plastics material such as polypropylene and reinforced with glass fibers. A hexagonal stub shaft (60) is also molded of the same plastic material as the bushing. Each stub axle (60) is normally retained in its outwardly projecting position by a coil spring (68) located within shaft (35). The shaft member (35) defines an internal hexagonal chamber (52) and a slightly smaller hexagonal bore (54) with the collapsible outer portion of the shaft member. Additionally, the stub axle (60) has a twisted and tapered outer tip portion (62) with a hexagonal outer end surface (63). Nimmo""s rigid plastics material includes sufficient carbon particles to allow for dissipation of electrostatic charge.
b) U.S. Pat. No. 4,421,442-Agnoff describes a conveyor roller tube that has a tapered shuttle for engaging the conveyor""s frame. A roller (10) is mounted between the frame members (12) via an axially moveable shuttle (30) at the ends of the roller shaft (18). The shuttle (30) is adapted to engage its corresponding mounting hole (14) in the frame. Agnoff""s shuttle body (32) slides freely within the roller shaft (18) and has a polygonal tapered end portion (34) that is narrower the body (32) so that a shoulder (36) is created for engaging snap ring (38). Springs (42) always bias shuttles (30) toward their corresponding mounting holes (14). And in Column, lines 59-64, Agnoff declares, xe2x80x9cThe combination of the spring 42 and the tapered end 34 of the shuttle eliminates any play between the shuttle 30 and the mounting hole 14. As a result, vibration and movement of the roller shaft 18 is substantially reduced.xe2x80x9d
c) U.S. Pat. No. 5,865,290-Scott enables a conveyor roller insert. Scott""s cartridge has an outboard bearing (50) and inboard bearing (64). A stub axle (28) having a hex-shaped tip (30) is positioned axially within the cartridge (12) and roller tube (14). The tip (30) has a tapered portion (32) and projects outwardly from the cartridge (12) for inserting into a corresponding mounting hole (34). Scott incorporates a coil spring (40) for biasing the stub axle (28) into its corresponding mounting hole (34).
d) U.S. Pat. No. 6,076,647-Agnoff discloses a stub shaft conveyor roller. The roller tube (20) is journaled on a pair of stub shafts (50). Agnoff""s stub shaft (50) and bearing shield (40) are biased by a spring (60) to an extended position. Among other things, stub shaft (50) includes a cylindrical inner portion (52) journaled in bearing (38) and an outer hexagonal portion (54) adapted to mate with a similarly sized opening (14) of the mounting frame (12). Agnoff""s outer portion (54) also has a threaded hole (58) for receiving a bolt (62) which extends from outside the frame (12) into the hole.
e) U.S. Pat. No. 4,664,243-Martin enables a polymeric conveyor roller, a polymeric spherical bearing and a spring loaded retractable shaft.
f) U.S. Pat. No. 5,678,676-Pierson, among other things, teaches a method and apparatus for utilizing bushings to attach a conveyor roller rotably mounted on a through shaft to the conveyor frame. The bushing (36) is slipped over the end of shaft (14) and the tapered outer surface (41) of the tapered legs (40) are squeezed together to grip the roller shaft as it is inserted to the conveyor frame. When the bushing""s latches (39) and latching legs (38) are pressed through the hole, the latches (39) catch on the inner side (43) of the frame member to hold the bushing in place. The gripping action of the tapered leges (40) on the roller shaft greatly reduces vibration, and the bushing (36) eliminates the metal on metal contact between the shaft (14) and the mounting hole (22). In another embodiment, Pierson attaches a plastic cone (35) onto the roller shaft (14). And in yet another embodiment, the ""063 Patent discloses biasing the tapered end of the through shaft (14) into mounting hole (22) to reduce vibration of the shaft (14) in both mounting holes (22) and (32).
g) U.S. Pat. No. 5,875,878-Pierson is a Patent that issued from the divisional application from which U.S. Pat. No. 5,678,676-Pierson also issued.
h) U.S. Pat. No. 3,353,644-McNash, et. al., among other things, enables a conveyor roller formed of plastic components.
i) U.S. Pat. No. 3,610,387-Von Stein enables a conveyor roller. The Von Stein shaft (6) has a blind bore (40) that reciprocates with an axially movable plunger (42). A helical expansion spring (45) is inserted into the blind bore (40) to bias the head (44) of plunger (42) into hole (102) of frame.
Unlike traditional stub axles for cartridge bearings, the present apparatus includes a tip harder than the surface circumscribing the aperture of the fixed structured into which the stub axle it is to be inserted or a damper or both. Hexagonal and other tapered tips of the stub axle are sized for operatively interlocking with an aperture of the conveyor frame. Both the stub shaft and the stub axle engaging the stub shaft are electrically conductive to assist in grounding the static charge frequently generated by conveyor roller tubes. The cartridge""s housing can be supported by a single ball bearing, a ball bearing and a journal bearing, or by two ball bearings. Along with supporting the housing, the bearing or bearings journal the hollow stub shaft. A spring can be inserted into a chamber of the stub shaft to urge the stub axle axially outward and toward its corresponding aperture, and the stub axle can also be provided with an anchor for securing the stub axle.
An object of the present invention is to provide a cartridge bearing for coacting with a conveyor roller tube.
It is another object of the present invention to enable a method of using the cartridge bearing.
Still another object of the present invention is to provide a stub axle having a tip or tip zone with greater hardness than the surface circumscribing the aperture that is operatively interlocked with the stub axle.
Yet another object of the present invention is to provide a stub axle having a damper or damper zone capable of reducing vibration associated with conveyor rollers.
Still another object of the present invention is to provide an axially movable electrically conductive axle.
Yet still another object of the present invention is provide a metallic axially movable electrically conductive axle.
It is yet another object of the present invention to provide a nonmetallic axially movable electrically conductive axle.
Still another object of the present invention is to provide an axially movable electrically conductive axle that is part metallic and part nonmetallic.
An embodiment of the present invention can be described as a spring-assisted axially movable electrically conductive axle extending outwardly from a hollow shaft journaled in a bearing for operatively interlocking an aperture of a fixed structure comprising: a body engaging the hollow shaft with a tip projecting outwardly from the hollow shaft for operatively interlocking with the aperture, wherein the tip is harder than the exposed surface of the aperture and a nonmetallic damper positioned between said tip and said body.
Another embodiment of the present apparatus can be described an insertable cartridge coacting with a tube, comprising: a housing; a bearing supporting the housing and journaling the stub shaft; a spring for urging an axially movable electrically conductive axle into an operative interlocking with an aperture of a frame, wherein the axially movable electrically conductive axle further includes: a body engaging the stub shaft and a tip projecting outwardly from the stub shaft for operatively interlocking with the aperture and a nonmetallic damper positioned between said tip and said body.
Yet another embodiment of the present device can be described as an insertable cartridge coacting with a conveyor roller tube, comprising: a housing; an inboard bearing and an outboard ball bearing supporting the housing and journaling a stub shaft; a spring for urging an axially movable electrically conductive axle into an operative interlocking with an aperture of a conveyor frame, and wherein the axially movable electrically conductive axle further includes: a body engaging the stub shaft, a tapered tip projecting outwardly from the stub shaft for operatively interlocking with the aperture and a nonmetallic damper positioned between the tapered tip and the body.
In still another embodiment, the present invention can be described as an insertable cartridge coacting with a conveyor roller tube, comprising: a housing; an inboard ball bearing and an outboard ball bearing supporting the housing and journaling a stub shaft having a chamber including a spring for urging an axially movable electrically conductive axle into an operative interlocking with an aperture, and wherein the axially movable electrically conductive axle further includes: a metallic body engaging the electrically conductive nonmetallic stub shaft and a metallic hexagonal tapered tip projecting outwardly from the stub shaft for operatively interlocking with the aperture of said frame such that the metallic tapered tip of the axially movable electrically conductive axle is harder than an exposed surface of the aperture.
Yet still another embodiment can be described as an insertable cartridge coacting with a conveyor roller tube, comprising: a housing; an inboard ball bearing and an outboard ball bearing supporting said housing and journaling a stub shaft having a spring for urging a hexagonal axially movable electrically conductive axle into an operative interlocking with an aperture, wherein the hexagonal axially movable electrically conductive axle further includes: a body engaging the stub shaft and a metallic tapered tip harder than an exposed surface of the aperture projecting outwardly from the stub shaft for operatively interlocking with the aperture and a nonmetallic damper positioned between the tapered tip and the body.
Still another embodiment of the present invention can be described as a method of operatively interlocking a tip of an electrically conductive axle to an aperture of a conveyor frame for reducing vibration and noise of a conveyor roller, comprising the steps of: inserting a cartridge including a ball bearing into an end of a conveyor roller; supporting the cartridge from said ball bearing; journaling a stub shaft in the ball bearing; loading a spring into the stub shaft for urging said electrically conductive axle body toward said aperture; incorporating a tip on said electrically conductive axle body, wherein said tip is harder than an exposed surface of said conveyor""s frame circumscribing said aperture; positioning a damper between the tip and the electrically conductive axle body; and operatively interlocking the tip of said electrically conductive axle body with the aperture.
It is the novel and unique interaction of these simple elements which creates the apparatus and methods, within the ambit of the present invention. Pursuant to Title 35 of the United States Code, descriptions of preferred embodiments follow. However, it is to be understood that the best mode descriptions do not limit the scope of the present invention.